Levels of 178Hf Populated in the Decay of 178m,gLu

Decay of 178m,g Lu has been studied by using Ge(Li), NaI(Tl) and plastic detectors. Sources were prepared by the 179 Hf(γ, p) 178m,g Lu reaction. Thirty-nine of forty γ-rays are assigned to the 178 Hf level scheme, which includes six newly observed levels at 1174.4( I π K =2 + 2), 1199.3(0 + 0), 1276.8(2 + 0) and 1322.4(3 - 2) keV in the 178g Lu decay and at 1364.04(9 - 8) and 1601.6(10 - 8) keV in the 178m Lu decay. Q β values are 2.05±0.05 MeV for 178g Lu and 2.25±0.03 MeV for 178m Lu. The most probable spin-parity assignments of 1 + and 9 - are proposed for the ground and isomeric states of 178 Lu, respectively. There is reasonable agreement between the experimental β branching ratios from 178m Lu to the 8 - band at 1147 keV and the Alaga rules. Discussions on the 178 Hf levels are made mainly on the basis of log f t values.

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